Condensation - I didn't expect that would happen

Discussion in 'Motorhome Chat' started by DavidG58, Jan 1, 2016.

  1. DavidG58

    DavidG58 Funster

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    Motorhome parked up at home, still plucking up courage to take for decent test drive before limping to France later this month, on hook up with Alde set to electric 1Kw, thermostat set to 12c, so no potential issues with freezing pipes

    Went across today to have a quick look, we only see the back from our house, had a frost last night, cars white over, presumed same for MH but by now had thawed, but inside windscreen was covered in condensation, far more than we normally get when in use on cold nights

    Karchered it, so all clear again, but why so much condensation with nobody in, the roof lights have built in vents and the Hartal lets a decent breeze round it ;), so think ventilation would have been good enough, no damp anywhere else, bedding feels nice, walls bone dry

    I always presumed the main part of the condensation was us breathing our moist air, but not been slept in for 2 months

    Should I be doing something different?
     
  2. GeriatricWanderer

    GeriatricWanderer Funster

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    Do you leave the base vehicle heater/blower set to windscreen? (Not blowing of course but still letting some upward airflow).
    I reckon ventilation is still the most likely culprit
     
    Last edited: Jan 1, 2016
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  3. olley

    olley Funster

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    Wind chill? Wind goes past the windows and they suffer wind chill, moist air inside the motorhome condenses on them. As you have vents open more moist air can come in and do likewise. Maybe the answer is to seal it up like a drum? Then only one load of moisture to condense. Got me thinking now, not good. :xblink:

    Ian
     
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  4. sallylillian

    sallylillian Funster Life Member

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    I have a small thermostatic controlled electric fan set on lowest to keep air warmish but moving and small dehumidifier set at 50% which needs emptying every 5-7 days.
     
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  5. DavidG58

    DavidG58 Funster

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    De humidifiers are scary things, I convinced myself many years ago they generate water to make themselves look effective :)

    We have one in our tanked and dry lined cellar that drags about a gallon of water a week out of nowhere (y)
     
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  6. Puddleduck

    Puddleduck Funster

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    We use a small dehumidifier as well (Aldi had them in just before Christmas). It usually has a cup or so of water in every day :) We also use a very small oil filled radiator set just above the frost stat.

    Last year I used one of the chemical dehumidifiers and that worked but not as well as the electric model.

    When the van is unoccupied I don't use the internal thermal screens as I think that would mean less ventilation around the cab. In our van I think it would be impossible to block all the ventilation holes - even if I wanted to :)
     
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  7. DavidG58

    DavidG58 Funster

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    I am on my way to check right now, seems a simple but potentially effective solution (y)

    just need the same conditions tonight to prove it :)
     
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  8. robnchris

    robnchris Funster

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    We take all soft furnishings out of the motorhome over winter, open all the cupboards, fridge etc.
    Never have any problems with condensation, if you heat the interior then warm air will settled on any cold surfaces and and you will get condensation, simple physics.
     
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  9. DavidG58

    DavidG58 Funster

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    A follow up point, probably the same as most others though, all windows in our MH are double glazed except the windscreen, which is the only one to get the condensation

    I don't pull the blinds
     
  10. Jimbohorlicks

    Jimbohorlicks Funster

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    I suspect your thermostat is too high at 12 C. This is extracting any moisture from the surroundings and because the windows are cooler ( direct contact with outside as it were) the moisture in the 12 C air is then condensing on the windows as opposed to elsewhere that is warmer. I would suggest a lower temperature setting would be better. The karcher would only put the condensate back into the warmer atmosphere in your van and will deposit the moisture again as condensate on the windows or anywhere that is cooler
     
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  11. DavidG58

    DavidG58 Funster

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    it might be simple to you, physics and me really did not get on at school

    actually simplify that, school and me didn't get on :D:D
     
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  12. pappajohn

    pappajohn Funster Life Member

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    Ventilation, not heat, is the cure for condensation.
    Warm moist air will condense on a cold surface.

    Keep the inside and outside temperatures the same and condensation cant form.
     
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  13. DavidG58

    DavidG58 Funster

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    I am on my way to open vents, will also drop the temp, we did use to set it at 8C not really sure why it got increased, or not lowered as far this year (y)

    the Karcher has only removed the condensation, it is one of the window cleaners (y)
     
  14. John Laidler

    John Laidler Funster

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    I suspect the condensation came from inside the vehicle, the cushions, any carpets or of course actual damp in the walls.

    A chemical dehumidifier would be worth trying, not too expensive. Or of course borrow the one from your cellar for a few days. They don't make the water, they draw it out of the air. In the case of your celler it will be coming originally from the walls and/or floor. Tanked or lined as it may be.
     
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  15. jezport

    jezport Funster

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    Dont leave the heating on. You're making warm moist air which condenses once it hits colder surfaces.
     
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  16. DavidG58

    DavidG58 Funster

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    I am right at the top of the lazy scale, by leaving heating on it saves dumping water, which I justify by being ready to pop off in at any moment, in reality not moved a wheel for 2 months and cost be a few £'s to keep warm :doh:
     
  17. robnchris

    robnchris Funster

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    Most roof vents have a natural air flow through them, as will your floor air vents, so unless you have things covering the floor vents preventing and or restricting the air flow your motorhome should be fine just left as it it without any heating of course.

    As for draining the water, it must take all of 5 mins to fill up the water so no bother really at all.
     
  18. Jimbohorlicks

    Jimbohorlicks Funster

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    Hi, not used a karcher but assume they are the steam ones for cleaning windows-I would suspect these will put more moisture into the air in your van and the upholstery etc. only for this to condensate when the air gets cooler or hits the windows on a cool day. You really need to remove the moisture from the air rather than just keep warming it up. open up the windows on a dry windy day.
     
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  19. DavidG58

    DavidG58 Funster

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    The Karcher we have is a battery powered suction pump with rubber blade, pretty nifty piece of kit for the bulk area of the windscreen, but no heat or steam involved (y)

    Agree with the opening up on dry day, will hope we get one before February :) we are planning to go away this month, hopefully best way to air it out (y) providing we can keep the dog dry :)
     
  20. scousebird

    scousebird Funster

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    In 20 odd years of caravanning/MHing we have never heated or dehumidified whilst not in use. Neither have we removed anything or left cupboards doors open, in fact we pretty much leave it ready to go. Never had an issue with damp.
     
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